Quick question; when sizing your chain, does it matter if the oval chain ring is in the vertical position?
Also, if anyone is interested, I have a spare (new) B Labs 32T oval chainring for sale. Get in contact if interested
The B Labs chain ring is the direct mount version.
First ride today on a 34t Absolute Black ring, really couldn't tell the difference on the flat or when going downhill but noticed it just felt ever so slightly smoother when climbing and a good chunk nicer when you're just kinda hoofing through a sharp steep bit in an unideal gear. It definitely didn't feel any worse on the flat though. Didn't lose the chain and it's not noisey. Overall pleased, it was bloody grim outside though with snow on parts of the trail...
[url= https://farm8.staticflickr.com/7469/16230600346_90af2f3a63.jp g" target="_blank">
[url= https://www.flickr.com/photos/129593813@N03/16230600346/ ]Untitled[/url] by [url= https://www.flickr.com/people/129593813@N03/ ]monkeyfudger[/url], on Flickr
So am I right in thinking a 32t one feels like a 34 through a portion of the pedal stroke?
FWIW - here is Pinkbike/Richard Cunningham's take on it:
http://www.pinkbike.com/news/absolute-black-oval-chainring-review.html
I'm been running an AB 32t one for a month or two now, firstly in place of a 30t N/W ring with gears. It felt strange/different for about 10 mins, then became unnoticeable. Climbing power/speed feels better. I've now switched the bike over to SS, and it runs very nicely. The chain does tighten and loosen slightly through 360 rotation, but I've set chain length so that it is fine at its tightest. Not dropped or skipped yet, so pretty happy with it.
I've had a couple of rides, circa 5 hours, on mine. 34t 1*10 on a 29er.
After the initial 15 minutes of it feeling really quite odd, ( I'm old enough to remember Biopace), I settled into riding with it and found zero difference on smooth trails/fire roads, either up or down hill, and at all cadences.
However I really like the way it seems to enable me to ke pedaling through bumpy rooty ground, the kind of awkward terrain that can slow you down in a race if you're not completely focused.
Definitely going to continue with it.
Been running 32 and 34 Absolute Blacks on a couple of 29ers for a good few hundred miles and I'm a convert. I notice the difference on any sort of climb that needs a bit of finesse or just low cadence grunt work. Not dropped a chain yet either.
Mate who is a big lad and very poor pedal stroke, so bad that can see power pulses in soft ground, had a go with one and noticed a huge difference. Still not put his hand in his pocket yet..
Very tempted by this, lots of sharp steep stuff locally.. I run a 36t normally, if I went 34t AB reckon it'd be easy as a 32t which I don't really want, anyone know of any good cheap 104BCD 36t or 38t rings?
I'll admit this is where I get confused. If I were to replace my 38T with an oval 38T would it be easier at certain parts or harder at others in comparison?
I'm also a little unsure of what to go for as i'm interested in the AB one.Going from a double 36/24 and 9 speed and tend to ride in the 36 on most stuff . So should i go 32 or 34t?
Anyone know if the goldtec oval Shimano chainrings fit a middleburn spider less crank (rs7) the splines look identical in the pic
For what it's worth I had a 22/24 inner (not really sure to be honest) and 38 outer on the XC bike, could manage most Scottish trail centre style stuff on the 38 and went for a 34 oval.
My understanding of the 'benefit' of the oval ring is that when you have a 32T fitted and you are climbing it feels like you are pedalling a 32T but you are in fact pedalling the equivalent of a 34T at the power point of your pedal stroke thus propelling you further over the ground.
I am happy to have this shot down in flames as I profess to.... guessing.
What I cannot even guess is the effect it will have on the suspension.
Will it increase/decrease chain growth?
Will it make the suspension less/more active over rough ground when pedalling hard?
Etc...
Tricky, goldtec direct mount to middleburn.
Cheers taz.. Can't seem to find them on the site?
Can anyone explain the difference between these modern rings and the old biopace ones that everyone says were rubbish?
PrinceJohn - Aren't they 90 degrees different. So where the biopace had their smallest radius, the new ones have their biggest radius and vice versa
Just installed my Bionicon 32T B-Ring today.. was going 1x10 anyway so seemed rude not to try it!
[IMG] 
[/IMG]
Not particularly noticeable on the 'ride around the garden' test, but will hopefully get out for a proper ride tomorrow. Not as ovalised as the AB ones either so not as pronounced an effect.
PrinceJohn - Aren't they 90 degrees different. So where the biopace had their smallest radius, the new ones have their biggest radius and vice versa
?
So why does that make them better?
The idea of the oval ring is that it effectively gives you a bigger gear during the part of the pedal stroke where you develop the most power. That being when the crank you're pushing down on is slightly past horizontal, around 1/3 of the way through the pedal stroke circle (starting from the top). They then give you a smaller gear through the part of the stroke where you don't put in any power, when you're feet are going over the top and under the bottom. Simply put, this means that you get much smoother power delivery and much less of a 'choppy' feeling as you pedal. To be clear, oval rings won't change how much power you can put out, they just even out the delivery. The old Shimano Biopace rings, as others have pointed out, were 90 degrees out. They gave a smaller gear during the part of the pedal stroke where you develop the most power - completely backwards to the current crop.
I use Rotor Q-Rings on my singlespeed and the road bike, couldn't go back! The chain tension is a little questionable on the ss, The chain wrap on the ring varies slightly as you go around, but it's a small enough difference that it still works. The only reason I don't have one on the XC bike too is that I can't find one with enough teeth for my archaic 26er!
Have a look at [url= http://sheldonbrown.com/biopace.html ]this on Biopace[/url]. Idea is different to these oval rings and is meant for different application. Generally regarded as a bit of a fail though.
Tricky, give me a kick on facebook and I'll see what I can sort for you.
I love when folks catch up...and to think a couple of years ago I was a snake oil merchant for suggesting that rotor q and goldtec rings worked a treat...
I still have a 48t biopace chainring in the shed 😳
I have a Doval 40t on the commuter. Works well. Subtle but smoother at bottom dead centre, especially when out of the saddle. Going to try a AB on the 29er next.
IMO the primary reason oval rings have taken so long to catch on is that biopace was a mess, and now 1x10 and 1x11 is popular it opens the door again.
I love when folks catch up...and to think a couple of years ago I was a snake oil merchant for suggesting that rotor q and goldtec rings worked a treat...
Pffft..... you are only 120+ years too late:
http://www.highpath.net/highpath/cycles/ovals/03.html
Sadly I'm old enough (and sad.enough) to have saved both my Biopae and Highpath rings! You, know just in case one might need them, come back in fashion etc.. Might build up an original Stumpy mk2 with its original parts, inc. Biopace one day.
Are BETD / Goldtec still making these. I've been looking and every time I check they seem to be out of stock. i got a onekey off Tazzy a couple or three years back and have ridden it nearly into submission, so time to get a new one.
get a absolute black over goldtec, closer to qx-1, cheaper, thick/thin & likely to be in stock more often. loving my spiderless and seems to work the mech out less, ditched goldtec with type 2 mech as chain growth was too much
I still have a direct mount B Labs 32T ring going spare if anyone is interested....
I was looking at some on ebay the other day that looked as if they had been melted.
More than just ovalised, but squashed and pulled into an odd shape.
I still have a direct mount B Labs 32T ring going spare if anyone is interested....
That's not the 104BCD one is it?
No this is the spiderless one. Much better if you have the right cranks. Lighter, simpler...
Bugger! Won't fit my XT cranks then 🙁
Holy thread resurrection batman....
I'm particularly interested if anyone with dodgy knees can report back on the performance on these, it's been suggested in some of their promotional material that it can help but not seen anything mentioned here or in other tests.
I have a variety of knee issues (ACL, meniscus, bone damage) that cause minor knee niggles when riding- Mainly slight knee popping on every pedal stroke and pain on occasion.
Just wondering if something like this might be beneficial for them?
